A circular disc of radius 7//pi cm is placed horizontally on the surface of water. Find the vertical force required to separated it from the water surface. (Surface tension of water =0.070N/m)

A circular disc of radius 7//pi cm is placed horizontally on the surfa

1.	A circular disc of radius 7//pi cm is placed horizontally on the surface of water. Find the vertical force required to separated it from the water surface. (Surface tension of water =0.070N/m)
Answer» Solution :The downward force on he circumference of the CIRCULAR disc `=Sxx2 pi R` WHER R is the rdius of the circular disc The VERTICAL force REQUIRED to separate it from the water surface = Downward force `F=Sxx2piR` `S=0.070N/m,R=7/(pi)cm=7/(pi)xx10^(-2)m` `F=0.070 xx2xxpixx7/(pi)xx10^(-2)=9.8xx10^(-3)n`